Terms of use
Plain rules for reading and sharing the site.
Updated November 11, 2026.
Using the site
You may read, link to and share duorolt.com for personal and educational use. Please do not copy the site in bulk, use it to train or fill other sites with our text, or interfere with how it works.
Educational purpose
The guides explain astronomy in simple terms. They are not a substitute for textbooks, research papers or teachers. They give no medical, legal or financial advice.
Quoting and copying
The text and drawings on this site belong to the duorolt.com editorial team. You may quote short passages if you credit duorolt.com and link to the page. Please ask before republishing a full guide.
Accuracy
We work to be accurate and we show the date each guide was checked. Science changes, and some values shift with new measurements. We do not promise that every figure is current. If you find an error, tell us at contato@duorolt.com.
Safety when observing
Never point binoculars or a telescope at the Sun without a solar filter made for that purpose. Eye damage can be permanent. Follow the manufacturer's instructions for any equipment you use.
Quiz and Star map
The quiz and the Star map are learning tools. They have no prizes and no value. Progress is stored in your browser and can be lost if you clear your data.
Third-party links
Guides link to agency and research pages. We do not control those sites and are not responsible for their content.
Changes
We may update these terms. The date at the top shows the latest version.